Andrii Koval

The article examines the justification for designing and creating the equipment to determine the characteristics of spatial force loading on physical models of continuous earthmoving machinery actuators in real time when digging the soil. It also discusses measuring and registering tools for recording the parameters of force load when developing the soil. Research objective: The creation of equipment and registering tools for determining the characteristics of spatial force load of complex mechanical systems. Research object: Operating equipment of trenching and excavation continuous earthmoving machinery. Research method: Experimental. As a result of the conducted research, measuring equipment has been developed in the form of a strain gauge suspension for model structures of the studied operating equipment for trenching and excavation machinery. The equipment enables real-time measurement of the magnitudes and coordinates of applying spatial components of external forces and their moments to the studied mechanical system. Based on strain gauge measurements, determining the magnitudes of external forces and their moments is provided mathematically and by adding or subtracting electrical signals received from strain gauges of corresponding pairs of strain links. A measuring and registering complex with a set of analog and discrete sensors has been developed to register actual loads applied to the studied operating equipment of earthmoving machinery. This complex enables measuring and registering the actual loads in the system with an accuracy of ± 5 % of the real value. The complex enables to read and record the received information on a micro SD memory card, to convert the received signals into digital code, and store the received information (measurement results) on a digital medium for its further processing and analysis. Key words: force, moment, mechanical system, strain measurement, earthmoving machinery, measuring complex, sensor, memory card, digital code, amplifier, strain gauge module

Summary. The article addresses the issue of ensuring stable operating conditions for continuousoperation earthmoving machines and other specialized machinery when subjected to lateral forces in the contact zone between the tracked undercarriage and the supporting surface. Such a situation is highly likely, particularly when earthmoving machines operate on uneven or complex terrain. Additionally, trenching and excavation machines working in a fan-like reciprocating motion mode also experience lateral force effects. The comprehensive challenge of preventing earthmoving machines from slipping due to lateral forces, whether on horizontal surfaces or slopes, requires an initial analytical solution. Slippage in machines operating in a turning mode can be eliminated by preventing the less-loaded track from slipping during movement. This study presents a computational model and derives dependencies for determining the longitudinal and lateral forces acting on the tracked undercarriage, as well as the resistance moment to turning, which causes a shift in the turning pole of the track chain resting on the ground. It is shown that to determine the permissible value of the lateral force that prevents sideward displacement of the tracks, it is necessary to establish an acceptable combination of longitudinal and lateral forces acting on the undercarriage, along with the corresponding resistance moment to turning. The potential rotation of the lower track branch during machine slippage occurs around a turning center that does not coincide with the track’s support surface center. The kinematics of track movement during machine slippage are analyzed, and the forces acting on the track in this scenario are determined. Calculations confirm the dependence of the force interaction characteristics between the tracked undercarriage and the supporting surface on the changing coordinates of the machine’s turning center. Keywords: earthmoving machine, soil, slope, lateral force, slippage, turning center, support surface center, track, variation coefficient

Problem. From the analysis of the technical literature, it was established that among the trenchless technologies for laying underground engineering communications and service pipelines, the technology with the possibility of forming a horizontally directed communication cavity in the soil using soil-piercing installations of static action is the most common. Goal. This method consists in forcefully pressing a soil-piercing working body, which has the form of a conical-cylindrical projectile, into the soil. At the same time, the well is formed by radial extrusion of the soil around the formed well. However, the use of such equipment does not provide high accuracy, which limits its practical application within 20 m. It is not sufficient for modern requirements of creating transitions during the laying of communications. Methodology. One of the ways to improve the efficiency of laying underground networks is to extend this method over a longer distance by correcting the trajectory of the working body. This is achieved by using a soil-piercing head with an asymmetric tip. Due to this, in addition to the axial resistance of the soil, a transverse component force appears, which deflects the head during its advancement in the soil. The question of determining the angle of displacement of such a tip is important in terms of the process control. Results. In the paper, a calculated dependence is proposed for determining the rational value of the angle of inclination of an asymmetric tip working surface, which is a flat plane cut at the angle of a cylinder. An analysis of the dependence of the angle of the working surface inclination on the physical and mechanical properties of the soil is also given. Originality. It was determined that the maximum angle of inclination of the frontal surface is determined by the conditions of soil descent from it. Its maximum value, for example when working in loam, should not exceed 55o-67o for a tip made of steel. Practical value. The obtained calculated dependence can be useful for determining the angle of inclination of the flat frontal surface of the tip of the soil piercing working tool for controlled static soil piercing at the stage of designing networks and choosing an effective method for drilling a well under roads or other obstacles.

Summary. This paper addresses the optimization of the structural parameters of the lifting mechanism of the frame for the working equipment in a universal rotary earthmoving trenching and excavation machine operating continuously. The goal is to reduce the efforts in its hydraulic cylinders while maintaining the prescribed kinematics of the mechanism. Structurally, the lifting mechanisms of the working equipment are designed with the hydraulic cylinder positioned above the boom (frame), and the fluid is supplied to the rod chamber of the hydraulic cylinder for lifting. The formulated optimization task aims to design a mechanism that could reach initial and final positions while simultaneously developing minimal peak effort on the hydraulic cylinder rod. Known as a "minimax" problem, this task seeks the minimum value among a set of maximums. Variables chosen include the linear distances from the axis of rotation to the hydraulic cylinder attachment points and the structural angle; a target function is defined. Computational dependencies for determining the design parameters and the force on the hydraulic cylinder rod are presented. Additionally, a constraint on the range of values for the structural angle parameter has been introduced. For calculations, a spreadsheet processor MS Excel with the "Solver" add-on was used. As a result of the optimization for the physical model of the working equipment of the universal rotary earthmoving trenching and excavation machine operating continuously, the parameters for the positioning of the hydraulic cylinder attachment points were found to reduce the load on the hydraulic cylinders by 1.39 times while maintaining the prescribed kinematics of the mechanism. The proposed methodology can be recommended for use in calculations of other lifting mechanisms where the cylinder is positioned above the boom and the fluid is supplied to the rod chamber of the hydraulic cylinder. Keywords: hydraulic cylinder, earthmoving machine, force, working equipment, force calculation, software, link-lever mechanism

This article addresses the creation and optimization of designs for Universal Continuous-Action Earthmoving Machines (UCAEM) capable of excavating extensive trenches of various widths, depths, and shapes without structural changes to the operating equipment. The paper provides a detailed rationale for the relevance and practical feasibility of developing continuous-action universal earthmoving machines. Analytically, the required trajectory of movement for the soil excavation operating element of UCAEM in the process of constructing wide trenches (excavations) in the soil is determined. This trajectory resembles a Bernoulli lemniscate, along which the operating element of UCAEM moves to excavate the soil in evenly thick planar chips. This enables the construction of trenches in the soil with maximum work productivity, minimizing external loads on the earthmoving machine's operating element. To implement the above, a physical model of the rotary operating equipment of UCAEM was created, and experimental studies were conducted. The design of the UCAEM operating element movement drive is based on a two-circuit lever mechanism with fifth-class rotary pairs, providing the delivery of the soil-excavating operating element to the soil face. Soil excavation is carried out in the mode of fan-linear feed of the operating element to the face. The movement of the operating element in the face is performed by a lever mechanism with three degrees of freedom, each link of the mechanism is provided with an individual turning drive using a pair of hydraulic cylinders relative to the hinge of its attachment. An algorithm for the operation of the drive for the movement to the face of the two-circuit soil-excavating rotary operating equipment of continuous-action UCAEM has been synthesized, providing soil excavation with chips of uniform thickness in plan, regardless of the width of the trench, and consequently, increasing the productivity of the machine's operation. Equalization of the chip thickness in plan is achieved by turning the intermediate frame of the operating element at the end of each half-cycle of the working process. An algorithm for the movement of the operating element during the construction of entry and exit ramps during the construction of trenches in the soil over several passes of the operating element has been justified.

The article provides an analysis of the technical condition of main pipelines and technologies for performing selective overhaul of their linear part. Known technological schemes for performing selective repair of pipelines do not provide for effective soil compaction after its completion due to the lack of technical means for effective and uniform soil compaction. The lack of compaction of the soil under the repaired pipeline leads to its uncontrolled subsidence relative to the line of original laying, which can cause an emergency situation. In order to ensure high-quality, fast and safe execution of the entire complex of earthworks during the selective overhaul of main pipelines with one excavator, a research and industrial universal set of interchangeable work equipment for a single-bucket crawler excavator weighing 20 tons has been designed, manufactured and tested. The set of replacement equipment consists of digging equipment, compaction equipment, a bucket for performing earthworks during the opening of the pipeline and filling the soil in the trench, a universal grip for attaching the replacement equipment to the handle of a single-bucket excavator, a system for positioning and monitoring the position of the replacement equipment relative to the pipe. Technology for implementation of earth-moving works at capital repair of linear portion of main pipelines and complex of technological equipment for its realization are patented in Ukraine. The productivity of digging equipment is 35...55 m3/h, the productivity of compacting equipment is 35...45 m/h. The use of a set of equipment allows one excavator to perform the entire complex of earthworks during the selective capital repair of main gas pipelines with a diameter of 530...1420 mm.

This paper presents the problem of determination of stable transposition controllability conditions for the continuously operating earthmoving machine under conditions of working equipment mounting to the side from the base chassis (towing unit). The economical crisis in the country requires promising directions in the new technology creation, one of which is the creation of multipurpose towing units designated for mounting working equipment for different technological purposes. Such equipment can be mounted at the front, back, or side of the towing unit (chassis) and the machine created in such a way should not lose controllability in its operational mode. The characteristic feature of the machine for soil padding under the pipeline (МП-М) is the presence of two implements - upfilling and compaction implements. They have a rear overhanging position which unavoidably leads to displacement of the machines center of mass to the back side in relation to transverce axis and in the direction of the track that is near to the pipe in relation to longitudinal axis of the base chassis. Besides, at the moment of soil compaction under the pipe by the blade, In vertical component of the soil reaction appears in the compaction mechanism which leads to transverse dislocation of the pressure center towards the track that is farther from the pipe. Based on condidition of traction between tracks and soil, the minimal possible turning radius was determined for the machine for soil padding under the pipeline -МП-М in the working mode on the curvilinear section of the pipeline of different diameters.

This article considers external loads experienced on the rotor actuator of the universal continuous earthmoving machinery when digging wide excavations (ditches) in the soil and the ways to improve its productivity. Under the condition of translational and rotational supply of the soil-developing actuator to the face, the possibility of minimizing and leveling external loads on the actuator by improving the kinematics of its cyclic movement in the face has been experimentally proved. The actuator should move according to the required trajectory, which corresponds to the curve of the lemniscate of Bernoulli. The load of the UEM soil-developing actuator, operating in the mode of digging the soil, and the effectiveness of the suggested method for leveling the external loads have been experimentally assessed on the current physical model of the operating equipment. Leveling and reducing the absolute values of loads on the UEM operating equipment is achieved by improving the actuator trajectory optimization when digging the soil. It implies the additional rotation of the actuator intermediate frame at the end of each half cycle of the operating process. The required duration of the additional rotation of the intermediate frame is functionally dependent on the actual speed of machinery movement. The additional rotation of the intermediate frame, the duration of which is 1.1 s in the mode of maximum productivity, reduces the maximum load of the operating equipment, namely: torque on the rotor axis M_t-by 19% (up to 60 kN m), the components of the main force vector: vertical force-by 9% (up to 40 kN), and lateral force P_l.m-by 32% (up to 58 kN). The obtained results enable to comprehensively assess the maximum load of the UEM operating equipment under the conditions of changing values of the factors on which it depends and to objectively assess the directional stability of the machinery. Aligning the thickness of the shavings cut by the buckets of the rotor actuator in a half-cycle enables to improve the productivity of the universal earthmoving machinery almost twice.